2002 GMC Sonoma Owner's Manual - Page 313

CAUTION: You can be injured and your vehicle could be damaged if you try to do service work on a vehicle without knowing enough about it. D Be sure you have sufficient knowledge, experience, the proper replacement parts and tools before you attempt any vehicle maintenance task. D Be sure to use the proper nuts, bolts and other fasteners. "English" and "metric" fasteners can be easily confused. If you use the wrong fasteners, parts can later break or fall off. You could be hurt. Fuel (Gasoline) The 8th digit of your vehicle identification number (VIN) shows the code letter or number that identifies your engine. You will find the VIN at the top left of the instrument panel. See "Vehicle Identification Number" in the Index. If your vehicle has the 2200 L4 engine (VIN Code 5), you may use either regular unleaded gasoline or ethanol fuel containing up to 85% ethanol (E-85); also see "Fuel E-85 (85% Ethanol)" following. If your vehicle has the 4.3L V6 engine, use only regular unleaded gasoline. Gasoline Octane Use regular unleaded gasoline with a posted octane of 87 or higher. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it is bad enough, it can damage your engine. A little pinging noise when you accelerate or drive uphill is considered normal. This does not indicate a problem exists or that a higher-octane fuel is necessary. Adding Equipment to the Outside of Your Vehicle Things you might add to the outside of your vehicle can affect the airflow around it. This may cause wind noise and affect windshield washer performance. Check with your dealer before adding equipment to the outside of your vehicle. 6-3